This invention relates generally to a sampling and coring device for conducting geologic field work. More particularly, this invention relates to a low mass, multifunctional geologic sampling and coring device for interplanetary travel and for use in an extraplanetary environment, specifically Mars. Such extraplanetary operation includes collection of soil and rock samples in an uncontaminated, unchanged form at Martian ambient conditions.
Modern scientific research methods, particularly those involving handling and analysis of small objects, are conducted with the consensus that properly designed tweezers can greatly extend the functionality of the human hands. This consensus is demonstrated by the fact that tweezers are the most common hand instruments used in scientific laboratories. This fact was central to the development of the Space Holinser Forceps System, which has helped astronauts work under zero or micro gravity. The Space Holinser Forceps system contains more than 70 inter-connectable components and over 100 functional combinations. This system was found suitable for gripping objects of any shapes and up to 7.75 in. (20 cm.) in size under zero gravity or micro-gravity environment. Variants of the system have been used in the Russian space station MIR by the Russian astronauts manning the space station. The present invention is an extension of that concept, specifically applied to geologic sampling and coring.
After the series of Vikings and the Pathfinder missions, scientists concluded that the most scientifically and geologically useful secrets of Mars are undoubtedly hidden under the rind of its rocks or beneath its soil, thus indicating where the search for life on Mars should begin.
However, this created a contingent need for a device that could collect manipulate and analyze the Martian rocks and soil, while meeting the unique requirements of extraplanetary operation. The stringent requirements of interplanetary exploration include a requirement that the device be able to self-adapt to the Martian environment, survive large temperature fluctuations, and work in ambient temperatures as low as minus 80 degrees Celsius. Furthermore, a sampling and coring device suitable for interplanetary travel must be capable of surviving the high impulse shocks and accelerations on take-off and landing. Operationally, the device must be highly reliable, able to operate in a vacuum, and it must function with no outgassing. Due to the nature of space flight the device must have minimum mass and be anti-jamming, i.e. it must be capable of continuous operation despite physical obstructions, whether those obstructions are external or internal to the device.
Other functional requirements of such a machine include coring into hard igneous rocks with a power supply of less than 3 watts, a total mass of the unit not more than 400 gm. and a reaction force of less than 1 Kg. Vibration during operation must not be allowed to transmit back to the arm large enough to disturb the other instruments such as the cameras and microscope. These functional requirements plus the environmental requirements have resulted in many unique design features being developed in the machine that will be useful not only for interplanetary explorations but also for other use on earth.
There are analogies in the prior art, particularly in the field of underwater sampling. For example, U.S. Pat. No. 5,559,295 to Sheryll discloses an underwater sampling method and apparatus for collecting uncontaminated samples from an underwater environment at high in situ pressure. However, underwater sampling apparatus require many bulky features to permit the apparatus to function at relatively high ambient pressures. These features, such as thick-walled steel construction and—in the case of the Sheryll device—means for injecting fluids at high pressure to equalize internal and ambient pressures, add bulk and weight that make interplanetary transportation unfeasible or prohibitively expensive. Other limitations of the prior art are exemplified by U.S. Pat. No. 4,317,490 to Milberger et al., which relates to an underwater sampling device in which a sample tube and ball valve are operated from the water surface via a drill string. Such mechanical remote control systems as disclosed in the Milberger et al. device are naturally impossible for interplanetary sampling operations.